Tibial Insert

ABSTRACT

Disclosed herein are joint implants with sensors and methods for manufacturing joint implants with sensors. A knee joint implant according to the present disclosure may include a femoral implant, a tibial implant and a tibial insert disposed therebetween. The tibial implant may include a medial side with a medial central region defined around a medial center, a lateral side with a lateral central region defined around a lateral center and a central region disposed between the medial central region and the lateral central region. At least one sensor and a battery may be disposed within the tibial insert. The medial central region and the lateral central region may be defined by solid volumes extending from a proximal surface to a distal surface of the tibial insert.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 18/108,954 filed on Feb. 13, 2023, which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/444,056 filed Feb. 8, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/444,045, filed Feb. 8, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/443,146 filed Feb. 3, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/483,045, filed Feb. 3, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/482,659, filed Feb. 1, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/482,656 filed Feb. 1, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/482,097 filed Jan. 30, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/482,109 filed Jan. 30, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/481,660 filed Jan. 26, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/481,053 filed Jan. 23, 2023, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/431,094 filed Dec. 8, 2022, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/423,932 filed Nov. 9, 2022, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/419,781 filed Oct. 27, 2022, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/419,522 filed Oct. 26, 2022, and which claims the benefit of the filing date of United States Provisional Patent Application No. 63,419,455 filed Oct. 26, 2022, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/359,384 filed Jul. 8, 2022, and which claims the benefit of the filing date of U.S. Provisional Patent Application No. 63/309,809 filed Feb. 14, 2022, the disclosures of all of which are hereby incorporated herein by reference in their entirety.

FIELD OF INVENTION

The present disclosure relates to implants and methods for manufacturing implants, and particularly to joint implants with sensors and methods for manufacturing joint implants with sensors.

BACKGROUND OF THE INVENTION

Monitoring patient recovery after joint replacement surgery is critical for proper patient rehabilitation. A key component of monitoring a patient's recovery is evaluating the performance of the implant to detect implant dislocation, implant wear, implant malfunction, implant breakage, etc. For example, a tibial insert made of polyethylene (“PE”) implanted in a total knee arthroscopy (“TKA”) is susceptible to macroscopic premature failure due to excessive loading and mechanical loosening. Early identification of improper implant functioning and/or infection and inflammation at the implantation site can lead to corrective treatment solutions prior to implant failure. Data relating to postoperative range of motion and load balancing of the new TKA implants can be critical for managing recovery and identification of a proper replacement solution if necessary.

However, diagnostic techniques to evaluate implant performance are generally limited to patient feedback and imaging modalities such as X-ray fluoroscopy or magnetic resonance imaging (“MRI”). Patient feedback can be misleading in some instances. For example, gradual implant wear or dislocation, onset of infection, etc., may be imperceptible to a patient. Further, imaging modalities offer only limited insight into implant performance. For example, X-ray images will not reveal information related to the patient's range of motion or the amount of stress on the knee joint of a patient recovering from a TKA. Furthermore, the imaging modalities may provide only an instantaneous snapshot of the implant performance, and therefore fail to provide continuous real time information related to implant performance.

Therefore, there exists a need for implants and related methods for tracking implant performance.

BRIEF SUMMARY OF THE INVENTION

Disclosed herein are joint implants with sensors and methods for manufacturing joint implants with sensors.

In accordance with an aspect of the present disclosure a knee implant is provided. A knee implant according to this aspect, may include a femoral implant configured to be coupled to a femur, a tibial implant configured to be coupled to a tibia, and a tibial insert disposed between the femoral implant and the tibial implant. The tibial insert may include a medial side with a medial central region defined around a medial center, a lateral side with a lateral central region defined around a lateral center, a central region disposed between the medial central region and the lateral central region, and at least one sensor and a battery disposed within the tibial insert. The medial central region and the lateral central region may be defined by solid volumes extending from a proximal surface to a distal surface of the tibial insert.

Continuing in accordance with this aspect, the medial central region and the lateral central region may extend from an anterior surface to a posterior surface of the tibial insert. The at least one sensor and the battery may be located away from the medial central region and the lateral central region. The at least one sensor and the battery may be disposed within the central region. The at least one sensor and the battery may be disposed around a periphery of the tibial insert. The at least one sensor and the battery may be disposed around a periphery of the tibial insert.

Continuing in accordance with this aspect, the at least one sensor may include a Hall sensors and the femoral implant may include a magnet. The Hall sensor may be configured to track a location of the magnet. The at least one sensor may include a plurality of sensors. The plurality of sensors may include at least one load sensor. The plurality of sensors may include a temperature sensor, a pressure sensor, and a pH sensor. The at least one battery may include a plurality of batteries.

Continuing in accordance with this aspect, the tibial insert may further include a printed circuit board assembly, a processor, a charging coil, and an antenna, all of which may be located away from the medial central region and the lateral central region.

In accordance with another aspect of the present disclosure a method for manufacturing an implant is provided. A method according to this aspect, may include the steps of determining expected loading levels on an implant during implant life, identifying high load regions on the implant, and placing at least one sensor and at least one battery within the implant. The high load regions may represent implant regions determined to experience greater loading force than non-high load regions on the implant. The at least one sensor and at least one battery may be placed away from the identified high load regions.

Continuing in accordance with this aspect, the step of determining loading levels may be performed by a computer simulation of an implant model. The computer simulation may include a finite element analysis. The implant may be a tibial insert tibial insert configured to be located between a femoral implant and a tibial implant.

Continuing in accordance with this aspect, the method may further include a step of configuring the high load regions as solid volumes.

Continuing in accordance with this aspect, the method may further include a step of placing the at least one sensor and the at least one battery in a cavity of the implant and hermetically sealing the cavity. The at least one sensor may include a Hall sensor. The at least one sensor may include a plurality of sensors. The plurality of sensors may include at least one load sensor. The plurality of sensors may include a temperature sensor, a pressure sensor, and a pH sensor. The at least one battery may include a plurality of batteries.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the subject matter of the present disclosure and the various advantages thereof can be realized by reference to the following detailed description, in which reference is made to the following accompanying drawings:

FIG. 1 is a front view of a knee joint implant according to an embodiment of the present disclosure;

FIG. 2 is a side view of a femoral implant of the knee joint implant of FIG. 1 ;

FIG. 3A is a bottom view of the femoral implant of FIG. 2 ;

FIG. 3B is schematic view of encoder tracks of the femoral implant of FIG. 2 ;

FIG. 4 is a partial view of an encoder read head and a load sensor of a tibial implant of the knee joint implant of FIG. 1 ;

FIG. 5A is a front view of an antenna of the knee joint implant of FIG. 1 ;

FIG. 5B is a top view of the antenna of FIG. 5A;

FIG. 6 is a perspective side view of a knee joint implant according to another embodiment of the present disclosure;

FIG. 7 is a perspective front view of a tibial implant of the knee joint implant of FIG. 6 ;

FIG. 8 is a partial perspective view of an insert of the tibial implant of FIG. 6

FIG. 9 is a partial top view of the insert of FIG. 8 showing details of various insert components;

FIG. 10 is a perspective side view of the insert of the tibial implant of FIG. 7 ;

FIG. 11 is a perspective side view of a cover of the insert of FIG. 10 ;

FIG. 12 are graphs showing magnetic flux density measurements of the implant sensors and knee flexion angles;

FIG. 13 is a graph showing various implant sensor readings of the knee joint implant of FIG. 6 ;

FIG. 14 is a schematic view of implant sensors of the knee joint implant of FIG. 6 in communication with a processor;

FIG. 15 is a graph showing voltage measurements of the implant sensors;

FIG. 16 is a schematic view of a charging circuit for the knee joint implant of FIG. 6 ;

FIG. 17A is a graph showing measured voltage of the implant sensors;

FIG. 17B is a graph showing rectified voltage of the implant sensors;

FIG. 18 is a schematic view of a knee joint implant with a charging sleeve according to an embodiment of the present disclosure;

FIG. 19 is a front view of the charging sleeve of the knee joint implant of FIG. 17 ;

FIG. 20 is a side view of an insert of the knee joint implant of FIG. 17 ;

FIG. 21 shows top and front views of the insert of FIG. 19 ;

FIG. 22A is front view of a knee joint implant according to another embodiment of the present disclosure;

FIG. 22B is a side view of the knee joint implant of FIG. 22A;

FIG. 23A is a front view of a tibial implant according to another embodiment of the present disclosure;

FIG. 23B is a top view of an insert of the tibial implant of FIG. 22A;

FIG. 24A is a front view of a tibial implant according to another embodiment of the present disclosure;

FIG. 24B is a top view of an insert of the tibial implant of FIG. 24A;

FIG. 25A is a front view of a tibial implant according to another embodiment of the present disclosure;

FIG. 25B is a top view of an insert of the tibial implant of FIG. 25A;

FIG. 26 is a front view of a knee joint implant according to another embodiment of the present disclosure;

FIG. 27 is a front view of a tibial implant of the knee joint implant of FIG. 26 ;

FIG. 28 is a schematic side view of a knee joint implant illustrating various measurements according to another embodiment of the present disclosure;

FIG. 29 is a schematic side view of a spinal implant assembly according to another embodiment of the present disclosure;

FIG. 30 is side view of a hip implant according to another embodiment of the present disclosure;

FIG. 31A is a schematic view of a sensor assembly of the hip implant of FIG. 30 ;

FIG. 31B is a side view of the sensor assembly and an insert of the hip implant of FIG. 31A;

FIG. 31C is a top view of the sensor assembly and the insert of FIG. 31B;

FIG. 32 is a side view of a hip implant according to another embodiment of the present disclosure;

FIG. 33 is a partial top view of the hip implant of FIG. 32 ;

FIG. 34 is a side view of a hip implant according to another embodiment of the present disclosure;

FIG. 35 is a side view of an electronic assembly of the hip implant of FIG. 34 according to another embodiment of the present disclosure;

FIG. 36 is a side view of an electronic assembly of the hip implant of FIG. 34 according to another embodiment of the present disclosure;

FIG. 37 is a side view of a shoulder implant according to another embodiment of the present disclosure;

FIG. 38 is top view of an insert of the shoulder implant of FIG. 37 ;

FIG. 39 is a top view of a cup of the shoulder implant of FIG. 37 ;

FIG. 40 is side view of a shoulder implant according to another embodiment of the present disclosure;

FIG. 41 is a side view of an insert of the shoulder implant of FIG. 40 ;

FIG. 42 is a flowchart showing steps to determine implant wear according to another embodiment of the present disclosure;

FIG. 43 is a first graph showing implant thickness over time;

FIG. 44 is a second graph showing implant thickness over time;

FIG. 45 is a flowchart showing steps to determine implant wear according to another embodiment of the present disclosure;

FIG. 46 is a flowchart showing for implant data collection according to another embodiment of the present disclosure;

FIGS. 47A and 47B is a flowchart showing steps for patient monitoring according to another embodiment of the present disclosure;

FIG. 48 shows results of a loading simulation on a tibial insert;

FIG. 49 is an isometric view of a tibial insert and a tibial stem according to an embodiment of the present disclosure;

FIG. 50 is a cross-sectional view of a tibial insert according to an embodiment of the present disclosure taken along line B-B of FIG. 49 ;

FIG. 51 is a cross-sectional view of the tibial insert of FIG. 50 taken along a line A-A of FIG. 49 ;

FIG. 52 is a cross-sectional view of a tibial insert according to another embodiment of the present disclosure taken along line B-B of FIG. 49 ;

FIG. 53 is a cross-section view of the tibial insert of FIG. 52 taken along a line A-A of FIG. 49 ;

FIG. 54 is a cross-sectional view of a tibial insert according to another embodiment of the present disclosure taken along a line B-B of FIG. 49 ;

FIG. 55 is a cross-sectional view of the tibial insert of FIG. 54 taken along a line B-B of FIG. 49 ;

FIG. 56 is an isometric view of a tibial insert according to another embodiment of the present disclosure;

FIG. 57 is an isometric view of a tibial insert according to another embodiment of the present disclosure, and

FIG. 58 is a schematic view of an implant manufacturing process according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the various embodiments of the present disclosure illustrated in the accompanying drawings. Wherever possible, the same or like reference numbers will be used throughout the drawings to refer to the same or like features within a different series of numbers (e.g., 100-series, 200-series, etc.). It should be noted that the drawings are in simplified form and are not drawn to precise scale. Additionally, the term “a,” as used in the specification, means “at least one.” The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import. Although at least two variations are described herein, other variations may include aspects described herein combined in any suitable manner having combinations of all or some of the aspects described.

As used herein, the terms “load” and “force” will be used interchangeably and as such, unless otherwise stated, the explicit use of either term is inclusive of the other term. Similarly, the terms “magnetic markers” and “markers” will be used interchangeably and as such, unless otherwise stated, the explicit use of either term is inclusive of the other term.

In describing preferred embodiments of the disclosure, reference will be made to directional nomenclature used in describing the human body. It is noted that this nomenclature is used only for convenience and that it is not intended to be limiting with respect to the scope of the present disclosure. As used herein, when referring to bones or other parts of the body, the term “anterior” means toward the front part of the body or the face, and the term “posterior” means toward the back of the body. The term “medial” means toward the midline of the body, and the term “lateral” means away from the midline of the body. The term “superior” means closer to the head, and the term “inferior” means more distant from the head.

FIG. 1 is a front view of a knee joint implant 100 according to an embodiment of the present disclosure. Knee joint implant 100 includes a femoral implant 102 located on a femur 106 and a tibial implant 104 located on a tibia 108. Tibial implant 104 has a tibial insert 110 configured to contact femoral implant 102, and a tibial base plate or tibial stem 112 extending distally into tibia 108. Femoral implant 102 includes a medial encoder track 114 located on a medial side and a lateral encoder track 116 on a lateral side of the femoral implant. While the encoder tracks are shown along a surface of femoral implant 102 in FIG. 1 , these tracks can be located within or partially within a femoral implant on the medial and lateral sides thereof in other embodiments. The encoder tracks can be made of various structures, including magnetic tape of varying lengths and magnetic markers positioned at discrete locations. The resolution of the encoder track can be adjusted depending on the required precision of the measured parameters such as joint displacement, joint rotation, joint slip, etc. Tibial insert 110 includes a medial read head 118 and lateral read head 120 to read a magnetic flux density from medial track 114 and lateral track 116, respectively. Medial read head 118 and lateral read head 116 can be any suitable magnetometer configured to detect and measure magnetic flux density, such as a Hall effect sensor. As tibia 108 rotates with reference to femur 106 during knee flexion and extension, medial track 114 and lateral track 116 move along medial read head 118 and lateral read head 120, respectively. This movement causes a change in magnetic flux density which is detected by read heads 118, 120, and can be utilized to measure knee joint implant 100 movement, rotation, speed and range of articulation, motion/activity, joint slip, and other motion related information. The magnetic-mechanic coupling of the read heads with the encoder tracks allows for direct, instantaneous, and continuous measurements of these knee joint implant parameters. A data transmitter such as an antenna 122 located on tibial insert 110 transmits the knee joint implant parameters measured by the read heads via Bluetooth or other similar wireless means to an external source such as a smart phone, tablet, monitor, network, etc. to allow for real time review of the knee joint implant performance.

FIGS. 2-3B illustrate additional details of femoral implant 102, medial track 114 and lateral track 116. As shown in FIG. 2 , medial track 114 extends from an anterior portion 126 of femoral implant 102 to a posterior portion 128 of the femoral implant along a track axis 130. Medial track 114 includes a central portion 124 which is narrower than anterior and posterior portions 126, 128 as shown in FIG. 3A. As shown in FIG. 3B, medial track 114 includes arched or curved magnetic lines to compensate for joint rotations in order to maintain uniform readings during a full range of motion of the knee joint. Similarly, lateral track 116 extends from an anterior portion to a posterior portion of the femoral implant and includes a narrow central portion relative to the anterior and posterior portions with arched or curved magnetic lines. The conical profile and curved magnetic lines of the encoder tracks are configured to compensate for joint rotational motion and maintain alignment and coupling between the read heads and the tracks. This maximizes measurement collection and measurement accuracy during a full range of motion of the knee joint. The shape, size and location of the encoder tracks can vary depending on the implant.

FIG. 4 shows details of a medial side of tibial insert 110. Tibial insert 110 includes a medial load sensor 132 in connection with medial read head 118 via a medial connector 134. Medial load sensor 132 is a load measuring sensor such as a strain gauge or piezoelectric sensor configured to measure loads or forces transmitted from medial read head 118 via medial connector 134. Medial connector 134 can be a rigid member such as a connecting rod to transmit loads from medial read head 118 to medial load sensor 132. As shown in FIG. 4 , a portion of the medial side of femoral implant 102 directly contacts medial read head 118 to transmit loads (medial side loads), which is then measured by medial load sensor 132. Medial read head 118 is spring-loaded by a medial load spring 136 located below medial load sensor 132 to ensure contact between medial read head 118 and femoral implant 102. Similarly, a lateral side of tibial insert 110 includes a lateral load sensor, a lateral connector, and a lateral load spring. The lateral load sensor is configured to measure lateral loads between femoral implant 102 and tibial implant 104. Measured medial and lateral loads are transmitted via antenna 122 to an external source. Thus, knee joint implant 100 can simultaneously provide knee motion information (rotation, speed, flexion angle, etc.) and knee load (medial load, medial load center, lateral load, lateral load center, etc.) in real time to an external source.

Details of antenna 122 are shown in FIGS. 5A and 5B. Antenna 122 includes screw threads configured to be attached to tibial insert 110. Antenna 122 can include a coax interface to shield knee joint and improve transmission between knee joint implant 100 and the external source. A battery is located adjacent antenna 122 (not shown) to power knee joint implant 100. Antenna 122 can serve as a charging port via radio frequency (RF) or inductive coupling if a rechargeable battery is used. The location of battery and antenna 122 in tibial insert 110 allow for convenient access to remove and replace these components if necessary. Various other sensors such as a temperature sensor, pressure sensor, accelerometer, gyroscope, magnetometer, pH sensor, etc., can be included in knee joint implant 100 as more fully described below.

FIG. 6 is a perspective side view of a knee joint implant 200 according to another embodiment of the present disclosure. Knee joint implant 200 is similar to knee joint implant 100, and therefore like elements are referred to with similar numerals within the 200-series of numbers. For example, knee joint implant 200 includes a femoral implant 202, a tibial implant 204 with a tibial insert 210 and a tibial stem 212. However, knee joint implant 200 includes magnetic medial markers 214 and magnetic lateral markers 216 located at discrete locations along the medial and lateral sides of femoral implant 202, respectively.

Details of tibial insert 210 are shown in FIGS. 7-11 . Tibial insert 204 includes batteries 242 on both medial and lateral sides. Batteries 242 can be solid state batteries, lithium ion batteries, lithium carbon monofluoride batteries, lithium thionyl chloride batteries, lithium ion polymer batteries, etc. As best shown in FIG. 9 , Hall sensor assemblies, with each assembly including at least one Hall sensor, are used as a medial marker reader 252 and a lateral marker reader 248 to read medial markers 214 and lateral markers 216, respectively. Each Hall sensor assembly can include multiple Hall sensors arranged in various configurations and orientations. For example, the Hall sensor assembly can include Hall sensors oriented in Cartesian coordinates. As the tibia rotates with reference to the femur during knee flexion and extension, medial markers 214 and lateral markers 216 move along medial marker reader 252 and lateral marker reader 248, respectively. This movement causes a change in magnetic flux density, which is detected by marker readers 252, 248, to measure knee joint implant 200 movement, rotation, speed and range of articulation, motion/activity, joint slip, and other motion related information. The magnetic-mechanic coupling of the marker readers with the markers allows for direct, instantaneous, and continuous measurements of these knee joint implant parameters without the need to process this information via an algorithm or other means. While eight Hall sensor assemblies (four on each side) are shown in this embodiment, other embodiments can have more than eight or less than eight Hall sensor assemblies positioned at various locations. The arrangement of marker readers and markers provide absolute positions of knee joint implant 200 supporting wake-up-and-read kernels. Thus, no inference of movement by data synchronization techniques is required to obtain absolute position data of knee joint implant 200. The number of medial markers 214 can be different from the number of lateral markers 216 to account for variation in signal fidelity between these sides. For example, seven magnetic markers can be provided on the medial side and only four magnet markers can be provided on the lateral side to improve signal fidelity and motion detection precision on the medial side.

As best shown in FIG. 9 , three piezo stacks on the medial side serve as medial load sensors 232, and three piezo stacks on the lateral side serve as lateral load sensors 254. The staggered or non-linear arrangement of the three piezo stacks on the medial and lateral sides allow for net load measurements and identification of resultant load centers at the medial and lateral sides. Thus, knee joint implant 200 can simultaneously provide knee motion information (joint rotation, joint speed, joint flexion angle, joint slippage, etc.) and knee load (medial load, medial load center, lateral load, lateral load center, etc.) in real time to an external source. The piezo stacks are configured to generate power from the patient's motion by converting pressure on the piezo stacks to charge batteries 242 as more fully described below. Thus, knee joint implant 200 does not require external charging devices or replacement batteries for the active life of the implant.

Tibial insert 210 includes an infection or injury detection sensor 244. For example, the infection or injury detection can be a pH sensor configured to measured bacterial infection by measuring the alkalinity of synovial fluid to provide early detection of knee joint implant 200 related infection. A temperature and pressure sensor 246 is provided in tibial insert 210 to monitor knee joint implant 200 performance. For example, any increase in temperature and/or pressure may indicate implant-associated infection. Pressure sensor 246 is used to measure synovial fluid pressure in this embodiment. Temperature and/or pressure sensor 246 readings can provide early detection of knee joint implant 200 related infection. Thus, injury detection sensors 244 and 236 provide extended diagnostics with heuristics for first level assessment of infections or injury related to knee joint implant 200. An onboard processor 250 such as a microcontroller unit (“MCU”) is used to read sensors 244 and 236 and process results for transmission to an external source. This data can be retrieved, processed, and transferred by the MCU via antenna 222 continuously, at predefined intervals, or when certain alkalinity, pressure, and/or temperature thresholds, or any combinations thereof, are detected.

The various sensors and electronic components of tibial insert 210 are contained within an upper cover 256 and a lower cover 258 as shown in FIG. 10 . The upper and lower covers can be made from a polymer. Antenna 222 is located on an anterior portion of knee joint implant 200 to provide better line of site for transmitting data with less interference. The antenna is fixed inside the polymer covers to provide predictable inductance and capacitance. A cover 260 encloses the sensors and electronic components of tibial insert 210 as shown in FIG. 11 . Cover 260 can be a hermetic cover to hermetically seal tibial insert 210. Cover 260 is preferably made of metal and provides radio frequency (“RF”) shielding to the knee joint.

The modular design of knee joint implant 200 provides for convenient maintenance of its components. For example, an in-office or outpatient procedure will allow a surgeon to access the tibia below the patella (an area of minimal tissue allowing for fast recovery) to access component of knee joint implant 200. The electronic components and sensors of knee joint are modular and connector-less allowing for convenient replacement of tibial insert 210 or upgrades to same without impacting the femoral implant or the tibial stem.

Graphs plotting magnetic flux density measurements 310 and knee flexion angles 312 are shown in FIG. 12 . Magnetic flux density measurements 310 are generated from the magnetic-mechanic coupling of marker readers 248, 252 with the markers 214, 216 as more fully described above. Graphs 302 and 304 show magnetic flux density (mT) measurements from two Hall sensor assemblies (medial marker reader 252 or lateral marker reader 248) for a first range of motion of the knee joint. Similarly, graphs 306 and 308 show magnetic flux density (mT) measurements from two Hall sensors (medial marker reader 252 or lateral marker reader 248) for a second range of motion of the knee joint. The placement of magnetic markers 214, 216 on the femoral component create a sinusoidal magnetic flux density around femoral component 202. As the femoral component 202 rotates around an axis of rotation 201 shown in FIG. 6 , the marker readers read sine and cosine waveforms. The magnitude of the sine and cosine waves are interpolated to a near linear knee flexion angle. Placing the individual magnetic markers of medial markers 214 and lateral markers 216 at different separation angles on each condyle of femoral implant 202 creates a phase shift in the measurements from one condyle to the next as the knee rotates. This phase shift can then be used to correct for any rollovers in the interpolated waveform. Thus, marker readers 248, 252 and markers 214, 216 serve as an absolute rotation sensor measuring knee flexion through a full range of motion of knee joint implant 200. In addition to the two Hall sensor assemblies on the lateral and medial side of tibial insertion 210, the remaining Hall sensor assemblies of marker readers 248, 252 allow for 6-degrees of freedom movement measurements of knee joint implant 200 as more fully explained below. While an absolute magnetic encoder is disclosed in this embodiment, other embodiments can include a knee joint implant with an incremental magnetic encoder.

FIG. 13 is a graph showing various implant injury detection sensor readings 404 of knee joint implant 200 for early detection of knee joint implant related infection and/or failure. Pressure 408 and temperature 406 are measured using temperature and pressure sensor 246, and alkalinity 410 is measured using pH sensor 244 over time 402. As more fully explained above, alkalinity 410 measurements of joint synovial fluid can indicate bacterial infection to provide early detection of knee joint implant 200 related infection. Increase in pressure 408 and temperature 406 readings may indicate implant-associated infection. Variation or change in synovial fluid pressure 408 may indicate implant malfunction. In addition to predetermined absolute thresholds of the temperature, pressure and alkalinity readings indicating impending infection or implant failure, collective analysis of these readings can offer early detection warning ahead of the failure/infection thresholds. As shown in FIG. 14 , a combination of temperature, pressure and alkalinity may indicate early detection of trauma 414 or infection 412. Thus, injury detection sensor readings provide extended diagnostics with heuristics for first level assessment of infections or injury related to knee joint implant 200.

FIG. 14 is a schematic view of piezo stacks of medial load sensors 232 and lateral load sensor 254 in communication with a processor 266. Analog impulses generated by the piezo stacks when subjected to loading are converted to continuous digital signals via analog-to-digital converters 262 and 264 as shown in FIG. 14 . The continuous digital signals (voltage) 508 can be serially loaded into a shift register and measured as shown in a graph 500 of FIG. 15 . A sampling window 506 is selected to identify a peak reading 508 to detect knee joint motion. For continuous loading case, such as when a patient is standing, additional sensors such as an inertial measurement unit (“IMU”) located in the tibial insert or other locations on knee joint implant 200 can be used to detect or confirm knee joint position. Load data from piezo stacks and IMU measurements can be used to create load and motion profiles for patient-specific or patient-independent analyses.

FIG. 16 is a schematic view of a charging circuit 600 for charging battery 242 of knee joint implant 200. The charging circuit includes a charge circuit 602 connected to a charging coil 606 and piezo stacks of medial load sensors 232 and lateral load sensors 254 via bridge rectifier 604. Charging circuit is configured to direct charge to battery 242 utilizing inputs from one or more piezo stacks from the medial or lateral load sensors. This allows for singular or combined charging using individual or multiple piezo stacks. A minimum voltage output threshold of the piezo stacks can be predetermined to initiate battery charging. For example, when a patient is asleep, low piezo stack pulses will not be used to charge battery 242. Raw piezo stack pulses (voltage 704) as shown in a graph 700 of FIG. 17 over time 706 are rectified by a voltage rectifier 708 to produce a rectified and smoothed voltage output (voltage 704) shown in a graph 702 of FIG. 17B. The rectified and smoothed voltage output from the piezo stacks is used to charge battery 242. Thus, power harvesting from motion of knee joint implant 200 is achieved by using the pulses generated by the piezo stacks.

FIG. 18 is a schematic view of a knee joint implant 800 according to another embodiment of the present disclosure. Knee joint implant 800 is similar to knee joint implant 200, and therefore like elements are referred to with similar numerals within the 800-series of numbers. For example, knee joint implant 800 includes a femoral implant 802, a tibial implant 804 with a tibial stem 812 and a tibial insert 810. However, knee joint implant 800 includes a chargeable implant coil 872 located in tibial insert 810 which can be charged by an external coil 870 contained in an external sleeve 868 as shown in FIG. 18 .

External sleeve 868 shown in FIG. 19 includes an outer body 873 made of stretchable fabric or other material. Outer body 873 is configured to be a ready-to-wear pull-on knee sleeve which a patiently can conveniently put on and remove. A kneecap indicator 875 allows the patient to conveniently align sleeve 868 with knee joint implant 800 for proper placement of external coil 870 with reference to implant coil 872 for charging. As shown in FIG. 18 , when a patient aligns external sleeve 868 using kneecap indicator 875 and assumes a flexion position, external coil 870 is adjacent to implant coil 872 for proper charging. External sleeve 868 includes a battery 876 and a microcontroller 874 as shown in FIG. 19 . Battery 876, which can be conveniently replaced, provides power to external coil 870. In another embodiment, external coil 870 may be charged by an external source not located on sleeve 868.

FIG. 20 shows a side view of tibial insert 810 of knee joint implant 800. Tibial insert 810 is made of a polymer or other suitable to facilitate charging of implant coil 872. Implant coil 872 is located within tibial insert 810 at an indent or depression at a proximal-anterior corner of the tibial insert as show in FIG. 20 and FIG. 21 (top and front views of tibial implant 810). The proximal-anterior location of implant coil 872 maximizes access to external coil 870 for efficient and convenient charging.

FIGS. 22A and 22B show a knee joint implant 900 according to another embodiment of the present disclosure. Knee joint implant 900 is similar to knee joint implant 800, and therefore like elements are referred to with similar numerals within the 900-series of numbers. For example, knee joint implant 900 includes a femoral implant 902, a tibial implant 904 with a tibial stem 912 and a tibial insert 910. However, knee joint implant 900 includes a chargeable implant coil 972 located at anterior end of tibial insert 910 which can be charged by an external coil 970 (not shown). An external sleeve as described with reference knee joint implant 900, or another charging mechanism can be used to conveniently charge implant coil 972.

FIG. 23A is a front view of a tibial implant 1004 according to an embodiment of the present disclosure. Tibial implant 1004 is similar to tibial implant 204, and therefore like elements are referred to with similar numerals within the 1000-series of numbers. For example, tibial implant 1004 includes a tibial stem 1012 and a tibial insert 1010. However, tibial insert 1010 includes a charging coil 1072 located around a periphery of the tibial insert 1010 as shown in FIG. 23B. A spectroscopy sensor 1074 in tibial insert 1010 serves as an infection detection sensor for tibial implant 1004. Spectroscopy sensor 1074 is configured to identify the onset of biofilm on tibial implant (or a corresponding femoral implant) to provide early detection of implant related infection.

FIG. 24A is a front view of a tibial implant 1104 according to an embodiment of the present disclosure. Tibial implant 1104 is similar to tibial implant 204, and therefore like elements are referred to with similar numerals within the 1100-series of numbers. For example, tibial implant 1104 includes a tibial stem 1112 and a tibial insert 1110. However, tibial insert 1110 includes an IMU 1176 and five Hall sensor assemblies for each of the medial and lateral marker readers. The arrangement of the Hall sensor assemblies differ from tibial insert 210. Sensor data from IMU 1176 provides additional knee implant joint movement data as more fully explained above. For example, IMU 1176 can detect or confirm knee joint position during continuous loading positions of a patient such as standing. IMU data can reveal, or support measurements related to gait characteristics, stride, speed, etc., of a patient. pH sensor 1144 of tibial insert 1110 is located adjacent to a proximal face of the tibial insert at a central location as shown in FIG. 24B. All sensors of tibial implant 1104 are powered by batteries located in tibial insert 1110.

A tibial implant 1204 according to another embodiment of the present disclosure is shown in FIGS. 25A and 25B. Tibial implant 1204 is similar to tibial implant 204, and therefore like elements are referred to with similar numerals within the 1200-series of numbers. For example, tibial implant 1204 includes a tibial stem 1212 and a tibial insert 1210. However, tibial insert 1210 includes an IMU 1276 and a pressure sensor. Tibial insert 1210 is made of polyethylene and tibial stem 1212 is made of titanium in this embodiment.

FIG. 26 is a side view of a knee joint implant 1300 according to another embodiment of the present disclosure. Knee joint implant 1300 is similar to knee joint implant 200, and therefore like elements are referred to with similar numerals within the 1300-series of numbers. For example, knee joint implant 1300 includes a femoral implant 1302, a tibial implant 1304 with a tibial stem 1312 and a tibial insert 1310. However, battery 1342 of knee joint implant 1300 are located in tibial stem 1312 as best shown in FIG. 27 . Locating batteries 1342 in tibial stem provides room for additional sensors in tibial insert 1310. The tibial stem and tibial insert 1310 can be made of polyethylene in this embodiment. Various knee joint implant motion data 1301 collected by magnetic markers and marker readers is shown in FIG. 26 . Motion data 1301 can include internal-external rotation, medial-lateral rotation, varus-valgus rotation, etc.

A knee joint implant 1400 according to another embodiment of the present disclosure is shown in FIG. 28 . Knee joint implant 1400 is similar to knee joint implant 200, and therefore like elements are referred to with similar numerals within the 1400-series of numbers. For example, knee joint implant 1400 includes a femoral implant 1402, a tibial implant 1404 with a tibial stem 1412 and a tibial insert 1410. However, tibial insert 1410 includes an IMU 1476. Sensor data from IMU 1476 provides additional knee implant joint motion data 1401. Motion data 1401 can include internal-external rotation, medial-lateral rotation, varus-valgus rotation, etc. for reviewing knee joint implant 1400 performance. For example, internal-external rotation measurements exceeding a predetermined threshold can indicate knee joint implant lift-off (instability), medial-lateral rotation measurements exceeding predetermined thresholds can indicate knee joint implant stiffness. Combining these measurements with inputs from the various other sensors of tibial insert 1410 will provide a detailed assessment of knee joint implant 400 performance.

Referring now to FIG. 29 , a spinal implant assembly 1500 is shown according to an embodiment of the present disclosure. Spinal implant assembly 1500 includes a spinal implant 1510 such as a plate, rod, etc., secured to first and second vertebrae by a first fastener 1502 and a second fastener 1504, respectively. The first and second fasteners can be screws as shown in FIG. 29 . First fastener 1502 includes magnetic flux density detectors such as Hall sensor assemblies 1506 located along a body of the fastener 1502. Second fastener 1504 includes magnetic markers 1508 located along a body of the fastener. Any movement of second fastener 1504 with respect to the first fastener is detected and measured by Hall sensor assemblies 1506. Thus, the first and second fasteners function as an absolute or incremental encoder to detect spinal mobility of a patient during daily activity. As described with reference to the knee joint implants disclosed above, various other sensors such as temperature, pressure, pH, load, etc., can be included in fast fastener 1502 to provide additional measurements related to spinal implant assembly 1500 performance during a patient's recovery and rehabilitation. Ideally, there should be little to no movement between the first and second vertebrae for successful for spinal fusion. Therefore, any movement detected between the first and second fastener may indicate a compromised spinal implant assembly.

FIG. 30 is side view of a hip implant 1600 according to an embodiment of the present disclosure. Hip implant 1600 includes a stem 1602, a femoral head 1604, an insert 1606 and an acetabular component 1608. Magnetic flux density sensors such as Hall sensor assemblies 1626 are located on a flex connect 1628 and placed around femoral head 1604 as shown in FIGS. 31A and 31B. A connector 1622 on flex connect 1628 allows for convenient connection of femoral head 1604 with stem 1602. Magnetic markers 1630 are located on insert 1606 as best shown in FIG. 31C. Any motion of insert 1606 is detected by Hall sensor assemblies 1626 by measuring the change in magnetic flux density. Thus, Hall sensor assemblies 1626 and markers 1630 function as an absolute or incremental encoder to detect hip movement of a patient during daily activity.

Hip implant 1600 includes a charging coil 1610 located on stem 1602 as shown in FIG. 30 . Charging coil 1610 charges a battery 1612 via a connector 1624 to power the various sensors located in hip implant 1600. A load sensor 1614 such a strain gauge detects forces between stem 1602 and acetabular component 1608 to monitor and transmit hip loads during patient rehabilitation and recovery. Various electronic components 1616, including sensors described with reference to knee joint implants, are located in stem 1602. A pH sensor 1618 located on stem can measure alkalinity and provide early detection notice of implant related infection. Data from these sensors is transmitted to an external source via an antenna 1620 as described with reference to the knee joint implants disclosed above.

FIG. 32 is a side view of a hip implant 1700 according to another embodiment of the present disclosure. Hip implant 1700 is similar to hip implant 1600, and therefore like elements are referred to with similar numerals within the 1700-series of numbers. For example, hip implant 1700 includes a stem 1702, a femoral head 1704 and an acetabular component (not shown). However, battery 1712 of hip implant 1700 is located away from electric components 1716 as best shown in FIG. 32 . Battery 1712 can be conveniently inserted into hip implant 1700 via a slot 1734 as shown in FIG. 33 . Similarly, electric components 1716 can be inserted into hip implant 1700 via a slot 1732. This allows for convenient replacements and upgrades to the battery and electric components without disturbing hip implant 1700.

FIG. 34 is a side view of a hip implant 1800 according to another embodiment of the present disclosure. Hip implant 1800 is similar to hip implant 1600, and therefore like elements are referred to with similar numerals within the 1800-series of numbers. For example, hip implant 1800 includes a stem 1802, a femoral head 1804 and an acetabular component (not shown). However, slot 1832 of hip implant 1800 is configured to receive all electronic components structured as a modular electronic assembly 1801. A slot cover 1834 ensures that electronic assembly 1801 is secured and sealed in slot 1832. Thus, hip implant 1800 can be easily provided with replacement or upgrades to the electric components without disturbing hip implant 1800.

A first embodiment of a modular electronic assembly 1801 is shown in FIG. 35 . Electronic assembly includes a connector 1822 to connect to femoral head 1804, various electronic components 1816, a battery 1812 and an antenna 1820. Another embodiment of a modular electronic assembly 1801′ is shown in FIG. 36 . Electronic assembly 1801′ includes various electronic components 1816′, a battery 1812′, a load sensor such as a strain gauge 1814′ and an antenna 1820′. Electronic assembly 1801′ includes a pH sensor 1818′ to provide early detection of implant related infection.

FIG. 37 is a side view of a reverse shoulder implant 1900 according to an embodiment of the present disclosure. Shoulder implant 1900 includes a stem 1902, a cup 1904, an insert 1906 and a glenoid sphere 1908. Magnetic flux density sensors such as Hall sensor assemblies 1922 are located on insert 1906 as shown in FIG. 38 . A connector 1920 on cup 1904 as shown in FIG. 39 allows for attachment of the cup to insert 1906. Magnetic markers 1910 are located on glenoid sphere 1908 as best shown in FIG. 37 . Any motion of glenoid sphere 1908 is detected by Hall sensor assemblies 1922 by measuring the change in magnetic flux density. Thus, Hall sensor assemblies 1922 and markers 1910 function as an absolute or incremental encoder to detect shoulder movement of a patient during daily activity.

Shoulder implant 1900 includes a battery 1914 and an electronic assembly 1912 located within cup 1904. A pH sensor 1916 is located on cup 1904 to measure alkalinity and provide early detection notice of implant related infection. An antenna 1918 located on insert 1906 is provided to transmit sensor data to an external source to monitor and transmit shoulder implant 1900 performance during patient rehabilitation and recovery. Various electronic components 1912, including sensors described with reference to knee joint implants, are located in cup 1904.

FIG. 40 is a side view of a reverse shoulder implant 2000 according to another embodiment of the present disclosure. Shoulder implant 2000 is similar to shoulder implant 1900, and therefore like elements are referred to with similar numerals within the 2000-series of numbers. For example, shoulder implant 2000 includes a stem 2002, a cup 2004 and an insert 2006. However, electronic assembly 2012, battery 2014 and pH sensor 2018 are located in insert 2006 as shown in FIG. 41 . Thus, only a single component—i.e., the cup, of shoulder implant 2000 can be replaced or upgraded to make changes to sensor collection and transmission of the shoulder implant performance data.

FIG. 42 is a flowchart showing steps of a method 2100 to determine implant wear according to an embodiment of the present disclosure. While method 2100 is described with reference to a knee joint implant below, method 2100 can be applied to any implant with sensors described in the present disclosure, including all of the implants disclosed above. In a first step 2102, the initial thickness of the knee joint implant (such as thickness of the tibial insert) is recorded. This can be obtained by measuring the tibial insert prior to implantation, or measured based on the magnetic flux density generated by the magnetic markers as measured by the Hall sensor assemblies. Once the knee joint implant is implanted, periodic measurements of tibial insert thickness are determined in a step 2104 by evaluating the magnetic flux density. As the polyethylene housing of tibial insert degrades over time, the distance between the markers and Hall sensor assemblies are reduced as measured in a step 2106. This results in increased magnetic flux density values, which are used to estimate tibial insert wear in a step 2108.

The decision to replace the tibial insert can be based on a rate of wear threshold 2206 as shown in graph 2200 of FIG. 43 in a step 2110, or a critical thickness value 2308 as shown in graph 2300 of FIG. 44 in a step 2112. Graph 2200 plots tibial insert thickness 2202 over time 2204. A change in slope 2206 denotes the rate of wear of tibial insert. When slope 2206 exceeds the predetermined rate of wear threshold, notification to replace the tibial insert is triggered in a step 2114. Graph 3000 plots tibial insert thickness 2302 over time 2304. When the tibial insert thickness is less than a predetermined critical thickness value 2308, a notification 2310 is triggered to replace the tibial insert in step 2114.

FIG. 45 is a flowchart showing steps of a method 2400 to determine implant wear according to another embodiment of the present disclosure. While method 2400 is described with reference to a knee joint implant below, method 2400 can be applied to any implant with sensors described in the present disclosure, including all of the implants disclosed above. In a first step 2402, a knee angle of a patient with the knee joint implant is measured. The knee is then placed in full extension in a step 2404. Hall sensor amplitudes are measured in a step 2408. This process is repeated over time to track the Hall sensor amplitude. These values are then compared with initial Hall sensor amplitude values obtained when the knee implant joint template was implanted (obtained by performing steps 2412 to 2418). As the Hall sensor amplitudes are directly related to a distance between the markers and the marker readers—i.e., a tibial insert thickness, a difference between the initial Hall sensor amplitudes and current Hall sensor amplitudes from step 2408 represent wear of the tibial insert in a step 2420. When a predetermined minimum implant thickness is reached in a step 2420, a notification to replace the tibial insert is triggered in a step 2422.

FIG. 46 is a flowchart showing steps of a method 2500 for implant data collection according to an embodiment of the present disclosure. While method 2500 is described with reference to a knee joint implant below, method 2500 can be applied to any implant with sensors described in the present disclosure, including all of the implants disclosed above. In a first step 2502, a patient is implanted with a knee joint implant. The knee joint implant is in a low-power mode (to conserve battery power) until relevant activity is detected (steps 2504 and 2506). Once the relevant activity is identified by the sensor(s) of the knee joint implant (step 2508), the implant shifts to a high-power mode. Relevant activity to trigger the high-power mode can be patient-specific, and may include knee flexion speed, gait, exposure to sudden impact loads, temperature thresholds, alkalinity levels, etc. Upon identifying the relevant activity and switching over to the high-power mode, various sensors in the knee joint implant record and store sensor measurements on the device (step 2512). This data can be transferred from the patient to a home station when the patient is in the vicinity of the home station or a smart device (step 2514). The data is then transferred from the home station or the smart device to the cloud to be reviewed and analyzed by virtual machines and/or by experts (steps 2518, 2520). Relevant information for patient rehabilitation and recovery uncovered from the sensor data is sent back to the patient (steps 2523, 2522). Thus, method 2500 preserves and extends battery life of the knee joint implant by shifting the implant from low-power to high-power mode when required, and shifting the implant back to the low-power mode to conserve energy during other periods.

FIGS. 47A and 47B shows steps of a method 2600 for patient monitoring according to an embodiment of the present disclosure. While method 2600 is described with reference to a knee joint implant below, method 2600 can be applied to any implant with sensors described in the present disclosure, including all of the implants disclosed above. After installing the knee joint implant, various sensors within the sensor are activated (steps 2624, 2626) to track and monitor patient rehabilitation and recovery (step 2628). When the tracked data indicates that the desired recovery parameters are achieved, some of the sensors in the knee joint implant are deactivated or turned to a “sleep mode” (step 2616). For example, the recovery target can be a desired range of motion of the knee joint. Once a patient exhibits the desired knee flexion-extension range, some of the sensors on the knee joint implant can be turned off. Alternatively, peer data can be used to identify recovery thresholds (step 2612). If the recovery threshold or milestones are not achieved, the knee joint implant continues to charge and use all sensors (step 2608). Some sensors in the knee joint implant will be periodically used even after achieving the recovery milestones to monitor for early identification of improper implant performance (step 2610, 2618, 2620). For example, after turning off the magnetic readers upon achieving the desired flexion-extension range of motion, the pH or temperature sensors can be used to periodically measure alkalinity and temperature to identify infection or implant failure. Upon identification of an anomalous condition, the knee joint implant can be configured to fully recharge and turn on the previously turned off sensors to provide additional implant performance measurements (step 2624). A surgeon can customize the sensor readings and frequency based on the observed condition (steps 2626 and 2628). Additional rehabilitation steps for patient recovery can be provided to the patient at this point. The impact of the new rehabilitation steps can be monitored and compared with peers to observe patient recovery (steps 2636-2642).

FIG. 48 shows the results of a dynamic load simulation on a tibial insert 2700 performed using an FEA analysis. As shown here, dynamic loading on tibial insert 2700 during patient use (such as walking, standing, etc.) is not uniform across the tibial insert. Instead, high loading is concentrated specifically on medial 2702 and lateral 2704 centers of the tibial insert (shown as unshaded regions in FIG. 48 ). These locations are subjected to high loads and represent 20-100% of the peak von Mises stress and consequently are more vulnerable to failure than the rest of the tibial insert. Hence, reducing the thickness of the tibial inserts at the high stress locations to accommodate sensors, batteries, and other components for any of the implant disclosed herein (such as tibial insert 204) will weaken the tibial insert. Areas at the middle (between medial and lateral sides) and periphery of the tibial insert experience less loading than other areas as shown in FIG. 48 .

FIGS. 49-51 show a tibial insert 2800 and a tibial stem 2900 having a tibial baseplate according to another embodiment of the present disclosure. Tibial insert 2800 includes an opening 2803 to receive and couple with a complementary projection (not shown) of tibial stem 2900. As shown in the cross-sections of FIGS. 50 and 51 , sensors, batteries and other components of the knee joint implant can be located within the body of tibial insert 2800. Tibial insert 2800 includes a medial side with a medial center 2802 and a lateral side with a later center 2806 as best shown in FIG. 49 . A medial central portion 2804 defined by an oval or circular region around medial center 2802 and a lateral central portion 2808 defined by an oval or circular region around lateral center 2806 indicate the areas of tibial insert 2800 experiencing high/peak loading during implant life. Thus, the tibial inserts disclosed below are specifically configured to maximize strength, wear and fatigue resistance of these high loading areas by locating electronic and non-electronic component outside the high loading areas. While a circular or oval region is shown in this embodiment, other embodiments may have high loading areas defined by other shapes.

Referring now to FIGS. 52 and 53 , there is shown a tibial insert 3000 according to an embodiment of the present disclosure. Tibial insert is configured to accommodate the various electronic and non-electronic components of the smart implant within the tibial insert without weakening or otherwise comprising the structural strength and wear resistance of the implant during implant life. As shown in FIGS. 52 and 53 , electronic and non-electronic components are embedded within a sealed cavity 3001 defined by a layer 3004 located above opening 3002. Thus, as the medial and lateral centers of tibial insert 3000 (shown in FIG. 49 ) are not weakened by removing tibial insert material (cross-linked polyethylene or other suitable material) to accommodate electronic and non-electronic components, structural strength of tibial insert 3000 is maximized Layer 3004 can be cobalt-chromium, titanium, or other suitable material to form a hermetic seal and protect the electronic components from impact, subsidence, etc. during implant life. A cross-linked polyethylene material or other suitable material can be used to form a layer 3006 below cavity 3001 as best shown in FIGS. 52 and 53 . Layer 3006 can be reinforced to ensure improved coupling with the tibial base plate and stem. Underlaying layer 3006 prevents metal on metal contact between the electronic components in cavity 3001 and the tibial stem/base plate, and the formation of any wear particles resulting from the micromotion between these components. A void 3010 between layer 3004 and the body of tibial insert 3000 as shown in FIG. 53 allows for convenient mounting of layer 3004 within the tibial insert. For example, after locating all electronic and non-electronic components within cavity 3001, layer 3004 can be conveniently press-fit into tibial insert 3000 during assembly. A ceramic seal 3008 above a charging coil above a Bluetooth or RF antenna (not shown) allows for induction charging and wireless transmission of data while hermetically sealing cavity 3001.

FIGS. 54 and 55 show a tibial insert 4000 according to another embodiment of the present disclosure. Tibial insert 4000 is similar to tibial insert 3000, and therefore like elements are referred to with similar numerals within the 4000-series of numbers. For example, a cavity 4001 formed by a layer 4004 to accommodate and protect the electronic and non-electronic components of tibial insert 4000 therein. However, tibial insert 4000 includes a porous layer 4000 covering layer 4004 as best shown in FIGS. 54 and 55 . Porous layer 4000 can be bonded to the tibial insert (XLPE) articular surface. This bonding can be achieved by creating a porous structure on an interface, whereby the XLPE can be added to the metallic layer 4004 by over compression molding or other similar techniques.

FIG. 56 shows a tibial insert 5000 according to another embodiment of the present disclosure. Tibial insert 5000 includes a printed circuit board assembly 5008, a battery 5002, Hall sensors 5004, and a charging coil 5006. Battery 5002 is made of three sections: a first section extending along a posterior end of tibial insert 5000 and second and third sections extending from the posterior end to an anterior end of the tibial insert as best shown in FIG. 56 . In another embodiment, each of the battery sections can be separate batteries connected to each other or separate from each other to power particular components of the tibial insert. For example, a first battery can be used to power Hall sensors 5004, a second battery can be used to power the other sensors, and a third battery can be used to power data processing and transmission. All of the electronic and non-electronic components in tibial insert 5000 are located away from the medial and lateral centers which correspond to the high loading regions of the insert. These components are specifically located at areas within the tibial insert which experience minimum loading and forces as shown in FIGS. 48 and 49 . Thus, the medial and lateral centers of tibial insert 5000 are composed of entirely solid areas—i.e., with no cavities to accommodate electronic and non-electronic components. This ensures that the medial and lateral centers are of maximum thickness and strength to withstand high loading and impact forces that the tibial insert will experience during the life of the implant.

A tibial insert 6000 according to another embodiment of the present disclosure is shown in FIG. 57 . Tibial insert 6000 is similar to tibial insert 5000, and therefore like elements are referred to similar numerals within the 6000-series of numbers. For example, tibial insert 6000 includes a printed circuit board assembly 6008, a battery 6002, Hall sensors 6004 and a charging coil 6006. However, battery 6002 extends along a posterior end of tibial insert and has no extensions extending from a posterior to anterior direction. A portion of the printed circuit board assembly with the Hall sensors are located along medial and lateral peripheries of tibial insert 6000 as best shown in FIG. 57 . Thus, the medial and lateral centers of tibial insert 6000 are composed of entirely solid material with maximum thickness and strength to withstand high loading and impact forces experienced by the tibial insert.

Referring to FIG. 58 , there is shown a method 7000 for manufacturing a tibial insert according to an embodiment of the present disclosure. In a step 7002, a metal case configured to house the electronic and non-electronic components and a charging coil is assembled. The metal case does not have a bottom surface in this step. The open bottom surface is configured to receive the electronic and non-electronic components in subsequent step as described below. A direct compression molding or other similar process can be applied in a step 7004 to cover the metal case and coil with the tibial insert material such as XLPE, etc. The assembly of step 7004 can be irradiated or annealed in a step 7006. A suitable machining process can be used in a step 7008 to form the shape of the tibial insert. Electronic and non-electronic components of the tibial insert are now inserted and assembled through the open bottom surface of the machined tibial insert of step 7008 in a step 7010. The open bottom surface of metal case is now covered and sealed by laser welding or other suitable means in a step 7012. An additional layer of XLPE can be added to the cover any portions of the bottom cover of the metal case to prevent or reduce metal on metal contact.

While a knee joint implant, hip implant, shoulder implant and a spinal implant are disclosed above, all or any of the aspects of the present disclosure can be used with any implant such as an intramedullary nail, a bone plate, a bone screw, an external fixation device, an interference screw, etc. Although, the present disclosure generally refers to implants, the systems and method disclosed above can be used with trials to provide real time information related to trial performance. While sensors disclosed above are generally located in the tibial implant (tibial insert) of the knee joint implant, the sensors can be located within the femoral implant in other embodiments. Sensor shape, size and configuration can be customized based on the type of implant and patient-specific needs.

Furthermore, although the invention disclosed herein has been described with reference to particular features, it is to be understood that these features are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications, including changes in the sizes of the various features described herein, may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention. In this regard, the present invention encompasses numerous additional features in addition to those specific features set forth in the paragraphs below. Moreover, the foregoing disclosure should be taken by way of illustration rather than by way of limitation as the present invention is defined in the examples of the numbered paragraphs, which describe features in accordance with various embodiments of the invention, set forth in the paragraphs below. 

1. A knee implant comprising: a femoral implant configured to be coupled to a femur; a tibial implant configured to be coupled to a tibia, and a tibial insert disposed between the femoral implant and the tibial implant, the tibial insert comprising: a medial side with a medial central region defined around a medial center; a lateral side with a lateral central region defined around a lateral center; a central region disposed between the medial central region and the lateral central region, and at least one sensor and a battery disposed within the tibial insert, wherein the medial central region and the lateral central region are defined by solid volumes extending from a proximal surface to a distal surface of the tibial insert.
 2. The knee implant of claim 1, wherein the medial central region and the lateral central region extend from an anterior surface to a posterior surface of the tibial insert.
 3. The knee implant of claim 1, wherein the at least one sensor and the battery are located away from the medial central region and the lateral central region.
 4. The knee implant of claim 3, wherein the at least one sensor and the battery are disposed within the central region.
 5. The knee implant of claim 4, wherein the at least one sensor and the battery are disposed around a periphery of the tibial insert.
 6. The knee implant of claim 3, wherein the at least one sensor and the battery are disposed around a periphery of the tibial insert.
 7. The knee implant of claim 3, wherein the at least one sensor includes a Hall sensors and the femoral implant includes a magnet, the Hall sensor configured to track a location of the magnet.
 8. The knee implant of claim 7, wherein the at least one sensor including a plurality of sensors, the plurality of sensors including at least one load sensor.
 9. The knee implant of claim 8, wherein the plurality of sensors include a temperature sensor, a pressure sensor, and a pH sensor.
 10. The knee implant of claim 9, wherein the at least one battery includes a plurality of batteries.
 11. The knee implant of claim 9, wherein the tibial insert further includes a printed circuit board assembly, a processor, a charging coil, and an antenna, all of which are located away from the medial central region and the lateral central region.
 12. A method for manufacturing an implant, the method comprising: determining expected loading levels on an implant during implant life; identifying high load regions on the implant, the high load regions representing implant regions determined to experience greater loading force than non-high load regions on the implant, and placing at least one sensor and at least one battery within the implant, wherein the at least one sensor and at least one battery are placed away from the identified high load regions.
 13. The method of claim 12, wherein the step of determining loading levels is performed by a computer simulation of an implant model.
 14. The method of claim 13, wherein the computer simulation comprises of a finite element analysis.
 15. The method of claim 14, wherein the implant is a tibial insert, the tibial insert being configured to be located between a femoral implant and a tibial implant.
 16. The method of claim 12, further including a step of configuring the high load regions as solid volumes.
 17. The method of claim 12, further including a step of placing the at least one sensor and the at least one battery in a cavity of the implant and hermetically sealing the cavity.
 18. The method of claim 17, the at least one sensor includes a Hall sensor.
 19. The method of claim 18, wherein the at least one sensor including a plurality of sensors, the plurality of sensors including at least one load sensor.
 20. The method of claim 19, wherein the plurality of sensors include a temperature sensor, a pressure sensor, and a pH sensor. 